This invention relates to a method and device for packing bags or other flexible containers in an outer packaging, such as boxes. In particular, the invention relates to packing bags, filled with product, in such a way that the volume taken up by the bags in the outer packaging is essentially made up of product.
It is generally known in the state of the art to packing products such as deep-frozen French fries in bags. A number of bags are then placed, preferably upright, in an outer packaging, such as a box. A number of boxes are then placed on a pallet and this pallet is transferred from the packing location to a storage location and then to the sales location. Bags of this type are made such that they are permeable to gas.
In practice it has been found that an appreciable quantity of air is present in the bags when these are placed in the outer packaging, such as boxes. When boxes are placed on top of one another the lower boxes have to support the weight of the upper boxes. This support is partly provided by the product present in the boxes. Because the bags are permeable to gas, the load-bearing capacity of such a bag is low because the air gradually escapes from the bags. Consequently it is not possible to keep the boxes effectively in a stack in the longer term if the fill weight is relatively high. Such a high fill weight exists, for example, when the bags are filled with deep-frozen French fries. It must be understood that other products also give this problem.
In order to solve this problem it is proposed in the state of the art to remove air from the bags when closing. For this purpose a pipe or the like is brought close to the product at the open end of the bag before closing and a vacuum is generated during closing. The hose is removed as the final step in closing. Such a method is complex, gives rise to problems with sealing and makes it impossible to work at high speed.
In the prior art it is also proposed to subject the products to a vibratory treatment in order to put these into a bag more compactly. In such a vibratory treatment the bag is held between two plates, at least one of which is vibrating, and the distance between the two plates is then reduced. The volume of the bag is reduced as a result. However, it has been found that damage occurs to the product during this treatment. This applies in particular in the case of elongated products of low breaking strength, such as the French fries described above.
It is known in the prior art to move bags and other products by means of belts, arms and other constructions where vacuum is used to engage the bags or other packagings.
The invention relates to a method for packing products, comprising introducing said products into a gas-permeable flexible packaging, closing said flexible packaging and placing a number of flexible packagings in an outer packaging, wherein, after closing said flexible packagings and before placing them in said outer packaging, the residual gas volume in said flexible packagings is reduced, wherein said flexible packagings are placed on a support and means generating a vacuum are placed on the gas-permeable part of said flexible packagings in order to reduce the volume of said flexible packagings.
The means generating a vacuum can be applied both to the top of the flexible packaging and to the underside of the flexible packaging.
According to a particular aspect of the invention, vacuum for reducing the volume of said flexible packaging is generated by said support.
According to the invention the vacuum is not used for handling the flexible packaging but for removing air or other gases therefrom after the bags have been closed. Such removal of gases can take place within a relatively short time, it always being ensured that no damage occurs to the product. The flexible packaging can then be placed in an outer packaging and stacking of the outer packaging can take place without any risk.
According to a further aspect of the present invention, before the vacuum is applied a first portion of the gas present in the flexible packaging is removed by subjecting the flexible packaging to a vibratory treatment between two vibrating plates. In contrast to the prior art, it is not necessary to drive out the desired volume solely by means of this vibratory treatment, so that the risk of damage to the product present in the flexible packagings is appreciably reduced.
According to a further aspect of the present invention, vacuum is applied via a support and this support is movable and, for example, constructed as a conveyor belt. By this means vacuum can be applied for a relatively long time without delaying the production process. If a relatively short belt is used, this support can be movable in an indexing manner.
According to a further aspect the invention relates to a device for packing products, comprising a feed for products, a feed for gas-permeable film material, means for producing bags from said film material, filling means for introducing products from said feed into said bags, closing and separating means for closing and separating said bags, vibratory means for reducing the volume of said closed bags, vacuum-generating means for applying vacuum to said film material in order to reduce the volume of said closed bags, and placing means for placing a number of bags in an outer packaging.
The above aims, characteristics and advantages of the invention, and further aims, characteristics and advantages of the invention, will be described in more detail in the following description with reference to the appended drawing in which an illustrative embodiment of the present invention is given.